Ebola virus is an emerging, human pathogen causing deadly outbreaks of severe hemorrhagic fever. The molecular mechanisms of Ebola virus replication and pathogenesis are poorly understood, and consequently neither a vaccine, nor any specific antiviral therapy is currently available. Our preliminary data demonstrate that the VP24 protein of Ebola virus can function as a proton channel with pharmacological properties similar to those of the M2 protein of influenza A virus. The presence of an Ebola virus-encoded ion channel protein is rational since entry of Ebola virus is a pH-dependent process similar to that employed by influenza A virus. Importantly, the corresponding M2 proton channel of influenza A virus is the target of amantadine. Thus, it is likely that VP24 may serve as a similar target for the rapid development of anti-Ebola virus drugs. Our central hypothesis is that the VP12 protein of Ebola encodes a proton channel, and that this channel plays an important role in pathogenesis. Therefore, a better understanding of the structure and function of VP24 not only will provide insight into the molecular mechanisms of Ebola virus pathogenesis, but also may identify a novel therapeutic target for inhibiting Ebola virus replication. To define the biologically active structure and physiological/pathological functions of VP24 during Ebola virus infection we will, i) define domains within VP24 that regulate channel activation and proton permeation (Specific Aim 1), ii) identify domains within VP24 that are important for both biological structure and function (Specific Aim 2). iii) determine the pharmacological sensitivity of the VP24 channel protein, and assess the effect of pH regulatory drugs on Ebola virus infection (Specific Aim 3). iv) define the role of VP24/VP40 interactions in mediating assembly/budding of Ebola virus (Specific Aim 4). Overall this application will address key mechanisms of Ebola virus pathogenesis that may lead to the development of novel paradigms with direct impact on the development of therapeutic approaches.